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Discussion Starter #1
I have posted before about how soft my front springs are. They actually settle too much with just the weight of the bike on them when it's off the kick stand and then settles some more when I sit on it. I have put longer spacers on top of the springs, but it didn't do much. I have looked at a couple other Rebels and they do the same thing so it is not just my 500.



I really want to try some slightly stiffer springs and maybe some thicker fork oil, but I want to try the springs first because I feel that is the root of the problem. So, the 500 R and F share the same 41mm fork diameter with our Rebels but are a bit longer. The R and F have different part numbers so there is a difference, although I don't know what. Does anyone know if the R or F springs will fit our Rebels? And does anyone have any idea just how different the R and F springs are from ours? The fork springs are only $14 to $17 each so if they would actually fit, it would be a cheap experiment.


Thoughts? Ideas? Opinions?
 

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Discussion Starter #3
After spending some time reviewing front fork specs on the recent 500 offerings from Honda, I think the 500x springs would be my best bet. It looks like they are longer than the Rebel springs and the x is heavier than our Rebels. The fork springs in the '19 x are just a bit longer the the earlier ones. That may allow me some room to shorten them in case they would happen to be too stiff. At only $20 or so each, I think I will give them a shot.
 

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I'm sure you're aware that in case you're shortening a spring the spring rate will actually go up - so ot will be stiffer not softer.
 

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After spending some time reviewing front fork specs on the recent 500 offerings from Honda, I think the 500x springs would be my best bet. It looks like they are longer than the Rebel springs and the x is heavier than our Rebels. The fork springs in the '19 x are just a bit longer the the earlier ones. That may allow me some room to shorten them in case they would happen to be too stiff. At only $20 or so each, I think I will give them a shot.
You would be better off getting springs made for the bike.
https://www.ebay.com/itm/Honda-REBEL-500-2017-2018-YSS-Fork-Springs-LR355A075S390/302889624758?hash=item4685a0e4b6:g:IyUAAOSwDOlboLxl
 

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Discussion Starter #6
What makes those springs better? Just because the ad says for a Rebel? What do you know about them? Are they stock rate or different? And what exactly makes them worth that much more than factory Honda springs? Frankly, I didn't find any info in that ad that tells my anything about them. If you have solid information or experience with those aftermarket springs, I would be happy to hear it, especially what makes them 'better'.


We have swapped fork springs on dirt bikes many, many times over the years. Sometimes we have spacered them up and sometimes we have cut them down. And I have NEVER seen a case where shortening fork springs have made the front forks stiffer. Not once. Now Oyabun, this is twice that you have offered advice that is contrary to my experience. Against your advice, I have a 13t on the front of my bike and like every other time that I have had a 13t (or smaller) sprocket on a 520 chain, it is working just fine. So I am having the same success with that combo that Honda has had for decades. Surprised?



Unless the previous poster offers some good information or experience on the other 'unknown' brand of springs, I plan on spending the $40 or so on the Honda x springs for my 500. And if they happen to be too stiff, I will cut them down to soften the front end, just like I have done so many times before. Whatever happens, keep an eye on my posts because I will post the results. Whether good or bad. Because my experiments might just help someone else sometime.



It has always been my experience that real world experience trumps theory.........every time.
 

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We have swapped fork springs on dirt bikes many, many times over the years. Sometimes we have spacered them up and sometimes we have cut them down. And I have NEVER seen a case where shortening fork springs have made the front forks stiffer. Not once. Now Oyabun, this is twice that you have offered advice that is contrary to my experience. Against your advice, I have a 13t on the front of my bike and like every other time that I have had a 13t (or smaller) sprocket on a 520 chain, it is working just fine. So I am having the same success with that combo that Honda has had for decades. Surprised?

Unless the previous poster offers some good information or experience on the other 'unknown' brand of springs, I plan on spending the $40 or so on the Honda x springs for my 500. And if they happen to be too stiff, I will cut them down to soften the front end, just like I have done so many times before. Whatever happens, keep an eye on my posts because I will post the results. Whether good or bad. Because my experiments might just help someone else sometime.
It has always been my experience that real world experience trumps theory.........every time.
LOL. It's not an advice, it's a fact, like it on not. Shortening a coil spring increases it's spring rate. Period. Look up any physics book and be amazed. Also adding spacers does not stiffen a spring, just adds preload - essentially changing the ride height. Same way if you're cutting a spring and does not compensate with the amount of spacer, the spring rate still goes up, but the preload on the spring is decreased. BTW as all Honda oem springs are dual rate - it does matter also which side you're cutting into. A dual rate spring essentially has a softer and a harder spring part, and the two are working together at the beginning of the travel, making the spring weaker than any of the individual springs. Then at a certain point - usually around 75-80% of total designed travel - one part of the spring is coil binding, leaving the other spring to do all the work. This essentially increasing the spring rate for the remainder of the travel trying to avoid bottoming of the forks. So cutting one end or the other will modify the crossover travel of the spring. You're better off if you're cutting from the spacer rather than from the spring.

The YSS aftermarket springs are designed for the non-140 pound average asian male, so are a lot closer to real world requirements. Also as per the link they are linear - what is preferred for all race suspension shops, being a lot more controllable - as damping cannot follow the changes in spring force of a multi rate spring.

p.s. I'm not arguing you, just stating facts. Stating that a coil spring will be softer if shortened is like believing that earth is flat, because your car is not rolling away when parked without a parking brake.
 

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Discussion Starter #8
Figures don't lie, but liars figure. Did you even read my original post and what my goals are? Additional preload alone may accomplish my goals of holding the bike up under it's own weight. And yes, I am familiar with progressive and dual rate springs and understand the impact of modifying them. I have done it before. But by your response, it does not appear that you have actually shortened fork springs. Have you? Your facts and figures do not take into account what happens in real life. Whether because of the loss of preload or because of the impact on rate, I can tell you from experience that shortening fork springs DOES NOT lift or stiffen the front end. You can site all the theory or quote all the books you want, but if you haven't tried it, don't preach book specs.



And Oyabun, I said nothing about spring rates when I mentioned the possibility of shortening the springs if necessary. I said it may soften the front end. As before, I think you have confused two different things with your book specs. You are hung up on spring rates but there are more factors than that that will impact my ride height and stiffness. Which is not to say that spring rates are unimportant (obviously they are) it's just that there are other factors in play that you do not seem to give any weight.



And you say that there are different rate springs side to side. Not according to Honda. Front fork springs on our bikes are the same side to side. Now, the ends of the springs are usually more progressively wound on one or both ends depending on the application, but they are the same side to side. Once again, as with your sprocket statement, you are in conflict with Honda, as well as with me. But soldier on, there.


Do us both a favor Oyanun, please stop with the text book specs. They do not seem to be coupled with any real world experience. I would really prefer that responses to my posts be based on real world experience. Because real world experience trumps theory, especially inexperienced theory...........every time!
 

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I mean, you arguing about the springs i suggested (which are made for the bike) have no specs. Yet you are trying to put a spring you don't know the specs for on a bike they were not made for and expect you will be able to guess how they will react?
Also the YSS "UNKNOWN" brand as you put it, is one of the bigger suspension companies in the world.
I don't see how you think going from a stock spring to a different stock spring is going to give you any real difference.
 

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Discussion Starter #10
Shorty, you are jumping to conclusions. My decision to try the 500x springs was made after I was able to acquire enough information on them to feel that they may do what I hope to achieve. First, they are for 41mm forks and will fit the Rebel. Second, they are longer than the Rebel's springs which should give a bit more preload on my bike. Third, the 500x is a heavier bike than the Rebel, so the spring rate should be higher. All of which is what I am looking for. Not exactly a shot in the dark. Oh and fourth, my Honda dealer will put them in my hands for less than $40. Why wouldn't I try them?



The YSS springs in the link that you posted have no info whatsoever. That is what I meant by unknown. And I asked you for info on them, but have not heard anything on that yet. If you have some information on the springs in the link, other than they are from one of the biggest suspension companies in the world, post it up and I will consider it. But at more than 3 times the cost of Honda's springs, it may be a tough sell.



All I have asked for on here was if anyone had any experience with any other front springs on our Rebels that would slightly stiffen them. I haven't gotten that, so I offered to experiment with some springs and report back. I certainly would not recommend products that I had no experience with and did not even know how they would perform. Which is what you did.
 

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@Dave, It took me quite a few days to cool down and be able to answer you in manners I consider acceptable.

I had to realise it is pointless to argue with you, because belief is something what cannot be changed (see religions) and people are even going to wars because their believes. What you state is a belief. If not, it's great to see a real superman on board who with his own will can defy physics. As it otherwise works for all the rest of us 100 times out of 100.

I bet you have never actually measured the real spring force of your cut springs. Just not to fool yourself thinking you've got a lighter spring by cutting it, I suggest a short and very easy experiment. Take an inexpensive old fork spring, measure it's unladen length, and record it. Then put a known weight on it (avoiding the spring to buckle out) and measure the compressed length of that spring. You should have a good measure of the spring rate of that given spring in travel vs. force.
Then cut off a significant part of that spring (just to avoid measurement errors if only changed a bit, so go for 25% or even 50% if you want to) and repeat the experiment. I guarantee you that the shorter spring will sag less supporting the same weight than the original length. Effectively meaning that it's spring rate went up, as it will take more mass to compress it than before.

BTW I don't have a Rebel front spring , but I have physical dual rate springs and measurements (including spring force charts) at hand from the 2013 and 2016 500F as well as the 2014, 2016, 2019 500x stock bikes, and also the linear springs from the Rally Raid/Tractive Level 1 and L2 front suspensions - so if you'd need any information regarding those, feel free to ask.
 

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Discussion Starter #12
The '19 500x front springs are on back order until the 17th. I should receive them a few days after that. I would welcome the spring rates on the the '19 500x springs as they are different from the earlier ones. But without the specs on the Rebel springs to compare to, there is not much use. As I said before, I compared the overall weights and fork travel between our Rebels and the 500x to arrive at my decision. And the cheat price of $40 for the x springs made the decision that much easier.



I have cut front coil springs a good number of times to lower the front end of both bikes and cars. My concern with my Rebel is ride height and to a lesser extent, how stiff the front is. Rate and preload both play a role in this. It seems that you are hung up on the rate and ignoring other factors like overall length and preload that is important to what I want to achieve. Remember, the front forks sag under the weight of the bike alone when taken off the kick stand, then sag some more when I sit on it. With as little front travel as our bikes have, that is unacceptable to me.


The only reason that trimming front fork springs came up, is IF the 500 x springs were too stiff at the top, I could take some preload out. Although I am a Mopar guy (which means that we don't have to mess with front coil springs since we have fully adjustable torsion bars) I have helped many of my GM buddies adjust their ride height by cutting the front coil springs, just as I have done with motorcycles.



As it stands now I have 3 choices: A) I can leave the front as is, B) try the $40 500x springs, C) try the $125+ aftermarket springs that I have not been able to get any info on or user reports on. So for $40, I have the x springs ordered. If they get me where I want then it's all good. If they are also too soft, I haven't lost much in trying. If they are too hard at the top, then I'll go hacking on them. With $40 invested, what's the worst that could happen?


Frankly, we have spent more time 'discussing' this matter than I will spend installing the new springs. And I could tell from the start that you were pretty worked up over this although I am surprised that you are so worked up that you had to take a time out. Oyabun, it's not worth it. You have stated your position very clearly and repeatedly; cut the spring and the rate goes up. No problem. But I am concerned about both rate and ride height which involves additional factors.



Here is a video from a major coil spring manufacturer showing the proper way to cut a coil spring to adjust ride height, just like I have done and seen done many times. If my original position got to you, then this may send you to the moon.


https://www.youtube.com/watch?time_continue=172&v=VHPosx2oStU
 

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@Dave23 Great that finally we got to the point that you admitted the factual error. I've went to lengths to correct it, as you were claiming something false, and this is a public forum so a many people can come to wrong conclusions if the basics are not correct.

The fork springs in the '19 x are just a bit longer the the earlier ones. That may allow me some room to shorten them in case they would happen to be too stiff.
Here you state that cutting the springs makes them less stiff - For which I simply answer they will not be softer but in fact stiffer.

I'm sure you're aware that in case you're shortening a spring the spring rate will actually go up - so ot will be stiffer not softer.
Later you claim that you have years of experience and then reassuring that you have cut springs for long years and in your experience the cut springs always came out softer - which is a wrong assesment

We have swapped fork springs on dirt bikes many, many times over the years. Sometimes we have spacered them up and sometimes we have cut them down. And I have NEVER seen a case where shortening fork springs have made the front forks stiffer. Not once. Now Oyabun, this is twice that you have offered advice that is contrary to my experience.
......
It has always been my experience that real world experience trumps theory.........every time.
After which I describe how it works, and draw your attention that you might mix ride height and change of preload with actual spring rate change.

LOL. It's not an advice, it's a fact, like it on not. Shortening a coil spring increases it's spring rate. Period. Look up any physics book and be amazed. Also adding spacers does not stiffen a spring, just adds preload - essentially changing the ride height. Same way if you're cutting a spring and does not compensate with the amount of spacer, the spring rate still goes up, but the preload on the spring is decreased. BTW as all Honda oem springs are dual rate - it does matter also which side you're cutting into. A dual rate spring essentially has a softer and a harder spring part, and the two are working together at the beginning of the travel, making the spring weaker than any of the individual springs. Then at a certain point - usually around 75-80% of total designed travel - one part of the spring is coil binding, leaving the other spring to do all the work. This essentially increasing the spring rate for the remainder of the travel trying to avoid bottoming of the forks. So cutting one end or the other will modify the crossover travel of the spring. You're better off if you're cutting from the spacer rather than from the spring.
brake.
And then finally arriving to the point where you diffuse your original statement and admit that you were wrong at the first point.

Frankly, we have spent more time 'discussing' this matter than I will spend installing the new springs. And I could tell from the start that you were pretty worked up over this although I am surprised that you are so worked up that you had to take a time out. Oyabun, it's not worth it. You have stated your position very clearly and repeatedly; cut the spring and the rate goes up. No problem. But I am concerned about both rate and ride height which involves additional factors.

Now back to our original programming:
Regarding CB500 spring details, the Service Manual is a good basic source.
https://www.hondarebel3forum.com/forum/attachment.php?attachmentid=28035&stc=1&d=1557663544

As per this, in fact the CBR500 springs are the longest with 405mm, 500x comes next with 386mm and 500f are the shortest with 381.

As a reference the stock CMX springs are 391mm long, so if only unladen spring length would be of importance, only the CBR500 springs would suffice.
https://www.hondarebel3forum.com/forum/attachment.php?attachmentid=28037&thumb=1

As I have a few CB500 springs around, I can give zou further details on those:
2016 CB500F fork spring - Length 372mm, sum active coil number: 38, wire dia:5mm, Wire outer diameter36,8mm, initial spring rate: 5,57N/mm
2013 CB500X fork spring - L 387mm, #active coils:32, wire dia: 4,8mm, OD:36,8mm, initial spring rate: 5,51N/mm
2019 CB500x fork spring - L 387mm, #active coils:37,5, wire dia: 5mm, OD:36,8mm, initial spring rate: 5,65N/mm

Now this is still only half of the picture. As you see the attached image, the two srings will behave very different under compression.
https://www.hondarebel3forum.com/forum/attachment.php?attachmentid=28039&thumb=1

Initially they will react with a lower spring rate (see rates above), but roughly about 110mm compression (including the initial preload, which is usually 10-20mm for standard forks) they will increase in spring rate due the dual rate spring setup. As the '16 spring has a big change in coil rates between the two parts of the spring, it will have a very significant The '19 has a lot less difference between the two parts of the spring, therefore the changeover will be a lot smoother. Depending on your preload figures the 120mm total fork travel of the Rebel might not even reach the crossover point of the spring - as the '19 X has a total of 149mm travel.

In case you're generally OK with the oem spring rates, I suggest to rather buy a set of aftermarket fork caps with spring preload adjustability - that way you can simply dial in the desired sag to the oem forks.
 

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Discussion Starter #14
I do not agree with your assessment of my position on this subject. You seem to read something different into what I write than what I meant. I appreciate the info on the springs. Although there are not enough specs on the Rebel springs for me to make a good comparison to the x springs. The 500x forks are listed as having more travel than the Rebel forks, but your specs show that the springs are basically the same length. Besides having more front travel the 500x is a heavier bike, which led me to believe that the springs could be a little stronger on my 500. Which may or may not be the case.



Recent posts show that a member has been happy with his aftermarket springs, but at $250-$300, they ought to be good.


The 500x springs that I ordered are back ordered for another week or so. I could still cancel them if necessary. But what I think I will do is to go ahead and try the 500x springs. For $40, it is a cheap experiment. And I think I will go to 15w fork oil. I already have longer spacers in there. They did not help which leads me to believe that the rate is just too soft for my liking. The OE spacers are plastic which makes making extra ones super easy. Longer or shorter as needed. A bit more cumbersome that adjustable caps, but a lot cheaper.



If this approach doesn't get it, I will look into the CBR springs. After seeing the info that you provided, it seems there is little chance that any of the stock springs will be too stiff, which makes this whole discussion..........................................................................................
 

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Discussion Starter #16
Still waiting on the 500x springs. Two ship dates have come and gone. Maybe next week. I just hope that the 500x springs help enough to avoid spending the several hundred dollars that the aftermarket springs cost. As it is now, 1/3 of the front travel is lost with just the weight of me and the bike. As you may know, the Rebel only has 4.3" of travel to begin with.
 

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As it is now, 1/3 of the front travel is lost with just the weight of me and the bike. As you may know, the Rebel only has 4.3" of travel to begin with.
I know I'm opening another can of worms. It might have been different at that time when you've raced, or you might have used different suspensions, but on street bikes 25-33% of rider sag (so essentially using up 1/4th to 1/3rd of suspension travel with rider and bike) is perfectly normal - so wouldn't need too much reduction. In fact, rider sag is required to allow the suspension to react to eg a pothole before topping out.

I know you don't believe me, I link some references:
.: Race/Rider Sag Calculator :. | NorWest Suspension LLC

Paul Thede's (Racetech) Suspension Bible on google books
https://books.google.hu/books?id=GWR_H3cMRLoC&pg=PA21&lpg=PA21&dq=racetech+rider+sag

MCN article on suspension sag
https://www.motorcyclenews.com/amp/new-rider/choosing-kit/2006/november/feb23-05-how-to-set-suspension-sag/

Btw, if you want to increase front suspension travel, you can also do it by swapping in cb500f damper rods for 120mm travel, pre-2019 500x damper rods for 140mm travel, or 2019 dampers for 150mm travel. Keep in mind that all these fork travel lengths are the maximum advertised values, reduced approx 12-15mm by the top out spring when measured installed in the fork.
 

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Discussion Starter #18
That much sag might be normal, but is just too much for me. And the front just seems too soft. But having said that, I don't think that I have ever bottomed them out. And I don't necessarily want more travel either. Just a bit higher and stiffer in the front. Not a lot and if the 500x springs ever come off back-order, I'll see if they are enough. Maybe it's just me, but the rear shocks seem a bit too stiff even on the lowest setting while the fronts are way too soft. I probably won't do anything with the rears, but I will find a way to stiffen the fronts.


Maybe just cut the front springs like Oyabun wants. Or how about stretching them? Nah, for now I'll just wait for the 500x springs.
 

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Discussion Starter #19
Well the 500X springs FINALLY landed. Had to grind a bit off the OD to get them in place but they went. Overall, they ride a bit stiffer and raised the front end about 3/8". Might be worth the $50, but I was hoping for more. I think the issue is the tighter coils at the bottom of the spring. They are just too soft. The wider coils above the tight ones seem to be okay as I have never bottomed them out. I would like to see what they would be like without the tighter coils at the bottom. Just the full length of spring with the wider spacing. Maybe take 4 springs and make 2?
 

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Discussion Starter #20
I think I finally have a combination that will work. And for only about $25. The two things that I had to do was to eliminate the tight coils at the bottom of the fork springs and to have more preload on the springs. When I only added preload with the stock or with the 500X springs, it only further compressed the tighter coils at the bottom without having any impact on ride height or firmness. And those same tighter coils on the heavier 500X springs also prevented any progress. So clearly those pesky tighter coils had to go.



I used the slightly heavier 500X spring that I already had for my mod, but a stock Rebel spring would do just as well. And a spring from Honda is only about $25. The tighter coils at the bottom of our springs make up about 1/3 of the spring. So I cut my original springs at the transition point between the tighter coils and the wider coils. I then cut the donor spring at the same point and then cut the remaining spring into 2 equal pieces. Conveniently, when the section of tighter coils is removed and replaced with 1/2 of the length of wider coils from a donor spring, the resulting overall length is basically the same as a stock spring. That meant that only one donor spring is needed for the conversion rather than two.


There is a plastic spacer between the spring and the cap on top of the fork. I cut a piece of 3/4" PVC to fit into the spacer for a bit more reinforcement. Then I took a flat washer that just fits inside the fork tube and welded the hole up so that I could use it as a plate on top of the spacer to push against. I then drilled and taped the aluminum cap on top of the fork. I threaded an all-thread bolt into the cap so that I could adjust the pre-load. A couple of inches of pre-load makes a noticeable difference. And with an adjustable pre-load, it can be set to personal preference. I thought about Heli-Coiling the cap, but there doesn't seem to be that much pressure on the threads. But adding steel threads there may be a good idea. Since I didn't add them, should the threads in my cap eventually fail, I'll post that.



The front does sit higher now and it is stiffer in the front. But is not too stiff at all at the pre-load that it is at now. I didn't change the fork oil only because I was too lazy to pull the forks. But a heavier oil would probably be a good idea with the stiffer springs. It may get the heavier fork oil this winter.


I see that the YSS springs just posted also eliminates the tighter coils in their replacement springs. And their pictures do a good job of showing almost exactly what my spring plate and cap look like. I just got this completed over the weekend and have only ridden the bike a couple of times. I plan to experiment with the pre-load some to see what I like. I actually used 4" long bolts, so I have plenty of adjustment available. Once I settle on the setting that I like, I'll swap in the proper length bolts so that there isn't a couple inches of bolt sticking out of my fork caps.
 
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